This achievement will take you a while (which is why only 9% have it). Under the Performance Tracker on the main screen, you can see that you need to accomplish the following:
*Play 150 games in one or more Be A Pro careers. This doesn't have to be the created Pro, you can get credit playing NHL Be A Pro. (I've mostly done this way. No, I don't have it yet, but I'm close.)
*Maintain at least A- grade overall.
*2 different player trophies in various Be A Pro careers (ie. not the Stanley Cup... the Art Ross and Hart trophies would work). Again, you can do this with more than one career.
The legend card is set up so that you can play two careers (an NHL season is 82 games, so 2 seasons will net you the 150 games).
*Turn off your line changes (so you're always on the ice).
*Turn off penalties/icing/offsides (so you don't hurt your Team Play)
*Bump up your shot power/accuracy settings, and score a bit. Assists are good, too.
*Checking players is also good for Team Play.
*Positioning is easy if you just keep moving to where the blue arrow tells you where to go... there's some leeway with that.
Or you can just play through 150 games, and you should pretty much get all the requirements anyway, especially on lower difficulty levels. It's the 150-game requirement that is by far the most difficult part of the achievement.